Lake Tschida — storage

Storage now, against this reservoir's own record

56.90 Mm³

Stored, September 2026

8th

Percentile among 77 Seps on record

-19.2%

Against the Sep 1991–2020 average

-18.7%

Change over the 12 months to 2026-09

Storage in September 2026 was lower than almost every other Sep on record, ranked against 77 other Seps held for this reservoir.

Storage, 1949–2026

Monthly mean storage

924 monthly values, 1949 to 2026

Monthly means of the publisher's daily record. Volume, not percentage of capacity — see below for why.

What the shaded periods are (0 events)

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

240 of 924 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 924 would be longer than this page and unusable with a screen reader.
Period	Lake Tschida (Mm³)
October 1949	0.449
February 1950	0.879
June 1950	87.9
October 1950	75.9
January 1951	72.8
May 1951	94.8
September 1951	82.0
January 1952	73.1
May 1952	95.6
September 1952	88.7
January 1953	75.2
April 1953	78.3
August 1953	94.1
December 1953	79.3
April 1954	99.6
August 1954	81.6
December 1954	73.7
April 1955	81.8
August 1955	90.4
November 1955	78.9
March 1956	77.6
July 1956	81.8
November 1956	67.4
March 1957	64.6
July 1957	94.1
November 1957	81.6
February 1958	77.1
June 1958	85.0
October 1958	67.1
February 1959	61.0
June 1959	88.7
October 1959	68.7
February 1960	62.5
May 1960	93.0
September 1960	83.3
January 1961	69.2
May 1961	70.1
September 1961	53.6
January 1962	50.7
May 1962	61.7
August 1962	82.4
December 1962	72.0
April 1963	81.6
August 1963	91.4
December 1963	73.1
April 1964	71.6
August 1964	90.5
December 1964	78.2
March 1965	77.3
July 1965	93.7
November 1965	76.0
March 1966	90.1
July 1966	98.9
November 1966	81.0
March 1967	103
June 1967	96.2
October 1967	70.0
February 1968	68.9
June 1968	81.6
October 1968	69.2
February 1969	69.6
June 1969	89.8
September 1969	84.3
January 1970	78.6
May 1970	130
September 1970	72.1
January 1971	72.4
May 1971	96.9
September 1971	76.1
December 1971	75.8
April 1972	99.1
August 1972	90.6
December 1972	88.0
April 1973	96.9
August 1973	75.0
December 1973	67.8
April 1974	82.7
July 1974	82.6
November 1974	63.4
March 1975	64.5
July 1975	94.8
November 1975	78.7
March 1976	94.6
July 1976	89.4
October 1976	67.8
February 1977	66.4
June 1977	98.6
October 1977	97.1
February 1978	94.4
June 1978	96.2
October 1978	85.1
January 1979	83.7
May 1979	97.2
September 1979	82.3
January 1980	76.4
May 1980	81.7
September 1980	76.5
January 1981	75.7
April 1981	79.5
August 1981	75.9
December 1981	82.1
April 1982	114
August 1982	88.9
December 1982	95.1
April 1983	96.9
August 1983	85.4
November 1983	84.6
March 1984	91.5
July 1984	90.3
November 1984	72.9
March 1985	79.8
July 1985	86.9
November 1985	72.6
February 1986	75.8
June 1986	95.5
October 1986	95.3
February 1987	95.9
June 1987	92.5
October 1987	72.5
February 1988	72.1
May 1988	82.4
September 1988	58.6
January 1989	58.7
May 1989	79.1
September 1989	58.6
January 1990	58.4
May 1990	58.7
August 1990	51.4
December 1990	47.5
April 1991	51.2
August 1991	46.4
December 1991	42.1
April 1992	48.0
August 1992	43.7
November 1992	41.4
March 1993	58.2
July 1993	78.4
November 1993	91.8
March 1994	94.2
July 1994	82.9
November 1994	78.3
March 1995	87.1
June 1995	84.9
October 1995	82.0
February 1996	84.8
June 1996	85.0
October 1996	71.7
February 1997	75.0
June 1997	85.3
September 1997	77.5
January 1998	74.5
May 1998	84.2
September 1998	80.6
January 1999	80.3
May 1999	84.8
September 1999	75.1
December 1999	72.9
April 2000	77.9
August 2000	74.6
December 2000	68.5
April 2001	85.9
August 2001	80.2
December 2001	68.7
March 2002	65.2
July 2002	74.3
November 2002	66.1
March 2003	81.8
July 2003	80.0
November 2003	68.5
March 2004	88.1
July 2004	78.0
October 2004	69.8
February 2005	72.9
June 2005	84.7
October 2005	70.9
February 2006	74.5
June 2006	78.7
October 2006	60.8
January 2007	61.3
May 2007	70.7
September 2007	65.7
January 2008	65.8
May 2008	67.0
September 2008	52.1
January 2009	55.3
April 2009	118
August 2009	79.6
December 2009	72.4
April 2010	87.9
August 2010	79.3
December 2010	76.7
April 2011	100
July 2011	85.9
November 2011	71.1
March 2012	77.5
July 2012	79.3
November 2012	71.8
March 2013	77.1
July 2013	80.7
November 2013	79.7
February 2014	78.4
June 2014	83.0
October 2014	74.7
February 2015	86.5
June 2015	83.2
October 2015	73.2
February 2016	70.9
May 2016	80.9
September 2016	66.8
January 2017	71.5
May 2017	79.9
September 2017	63.2
January 2018	65.1
May 2018	74.5
August 2018	74.2
December 2018	74.7
April 2019	88.1
August 2019	75.9
December 2019	75.8
April 2020	79.2
August 2020	69.8
November 2020	63.9
March 2021	67.4
July 2021	69.4
November 2021	53.9
March 2022	56.3
July 2022	82.0
November 2022	66.3
March 2023	71.0
June 2023	78.6
October 2023	71.7
February 2024	73.9
June 2024	78.3
October 2024	65.9
February 2025	66.2
June 2025	79.5
September 2025	70.0
January 2026	73.8
May 2026	74.6
September 2026	56.9

The reservoir's year

Seasonal storage profile

Each calendar month's reference average, against the most recent year

1991–2020 average
Most recent 12 months

Twelve separate averages, one per calendar month. A January average describes Januaries only. Months are plotted 1–12.

View the data behind this chart

Underlying data
Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	69.6	73.8
Feb	70.7	78.5
Mar	78.0	79.0
Apr	81.3	76.6
May	79.0	74.6
Jun	79.5	72.3
Jul	77.3	66.4
Aug	73.7	59.2
Sep	70.4	56.9
Oct	69.8	69.3
Nov	69.9	70.3
Dec	70.2	71.7

Why this page shows a volume and not a percentage

Percentage full is a division, and the denominator is missing

“Percentage full” is the figure a drought is discussed in, and it is stored volume divided by capacity. Capacity is published on several different bases — gross, usable, live, and the figure at a particular spillway or licence condition — and dividing a stored volume by the wrong one produces a percentage confidently wrong by the ratio between them, at exactly the moment the number matters most.

Hydrionis holds storage measurements for this reservoir and does not hold a compatible authoritative capacity figure for it, so percentage full is not calculated. The volume above is what was actually measured. Where you need a percentage, take the publisher’s own capacity on its own stated basis and divide it yourself — the source is linked below, and knowing which basis you used is the whole point.

Water level

Monthly mean water surface elevation

924 monthly values

An elevation above a datum, not a depth of water and not a distance below the crest. Levels at different reservoirs are measured against different datums and must not be read against one another; this line is comparable only with its own history. Elevation and volume are not proportional either — a metre near the bottom of a reservoir holds far less water than a metre near the top, because the surface area grows with height.

What the shaded periods are (0 events)

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

240 of 924 periods, evenly spaced across the record. Every value is in the download and the API; a table of all 924 would be longer than this page and unusable with a screen reader.
Period	Lake Tschida (m)
1949.75	554
1950.0833333333333	614
1950.4166666666667	629
1950.75	628
1951	628
1951.3333333333333	629
1951.6666666666667	628
1952	628
1952.3333333333333	629
1952.6666666666667	629
1953	628
1953.25	628
1953.5833333333333	629
1953.9166666666667	628
1954.25	630
1954.5833333333333	628
1954.9166666666667	628
1955.25	628
1955.5833333333333	629
1955.8333333333333	628
1956.1666666666667	628
1956.5	628
1956.8333333333333	627
1957.1666666666667	627
1957.5	629
1957.8333333333333	628
1958.0833333333333	628
1958.4166666666667	629
1958.75	627
1959.0833333333333	627
1959.4166666666667	629
1959.75	627
1960.0833333333333	627
1960.3333333333333	629
1960.6666666666667	628
1961	627
1961.3333333333333	627
1961.6666666666667	626
1962	626
1962.3333333333333	627
1962.5833333333333	628
1962.9166666666667	628
1963.25	628
1963.5833333333333	629
1963.9166666666667	628
1964.25	628
1964.5833333333333	629
1964.9166666666667	628
1965.1666666666667	628
1965.5	629
1965.8333333333333	628
1966.1666666666667	629
1966.5	630
1966.8333333333333	628
1967.1666666666667	630
1967.4166666666667	629
1967.75	627
1968.0833333333333	627
1968.4166666666667	628
1968.75	627
1969.0833333333333	627
1969.4166666666667	629
1969.6666666666667	629
1970	628
1970.3333333333333	632
1970.6666666666667	628
1971	628
1971.3333333333333	630
1971.6666666666667	628
1971.9166666666667	628
1972.25	630
1972.5833333333333	629
1972.9166666666667	629
1973.25	630
1973.5833333333333	628
1973.9166666666667	627
1974.25	628
1974.5	628
1974.8333333333333	627
1975.1666666666667	627
1975.5	629
1975.8333333333333	628
1976.1666666666667	629
1976.5	629
1976.75	627
1977.0833333333333	627
1977.4166666666667	630
1977.75	630
1978.0833333333333	629
1978.4166666666667	629
1978.75	629
1979	629
1979.3333333333333	630
1979.6666666666667	628
1980	628
1980.3333333333333	628
1980.6666666666667	628
1981	628
1981.25	628
1981.5833333333333	628
1981.9166666666667	628
1982.25	631
1982.5833333333333	629
1982.9166666666667	629
1983.25	630
1983.5833333333333	629
1983.8333333333333	629
1984.1666666666667	629
1984.5	629
1984.8333333333333	628
1985.1666666666667	628
1985.5	629
1985.8333333333333	628
1986.0833333333333	628
1986.4166666666667	629
1986.75	629
1987.0833333333333	629
1987.4166666666667	629
1987.75	628
1988.0833333333333	628
1988.3333333333333	628
1988.6666666666667	626
1989	626
1989.3333333333333	628
1989.6666666666667	626
1990	626
1990.3333333333333	626
1990.5833333333333	626
1990.9166666666667	625
1991.25	626
1991.5833333333333	625
1991.9166666666667	625
1992.25	625
1992.5833333333333	625
1992.8333333333333	625
1993.1666666666667	626
1993.5	628
1993.8333333333333	629
1994.1666666666667	629
1994.5	629
1994.8333333333333	629
1995.1666666666667	630
1995.4166666666667	629
1995.75	629
1996.0833333333333	629
1996.4166666666667	629
1996.75	628
1997.0833333333333	629
1997.4166666666667	629
1997.6666666666667	629
1998	629
1998.3333333333333	629
1998.6666666666667	629
1999	629
1999.3333333333333	629
1999.6666666666667	629
1999.9166666666667	628
2000.25	629
2000.5833333333333	629
2000.9166666666667	628
2001.25	629
2001.5833333333333	629
2001.9166666666667	628
2002.1666666666667	628
2002.5	629
2002.8333333333333	628
2003.1666666666667	629
2003.5	629
2003.8333333333333	628
2004.1666666666667	630
2004.5	629
2004.75	628
2005.0833333333333	628
2005.4166666666667	629
2005.75	628
2006.0833333333333	629
2006.4166666666667	629
2006.75	627
2007	628
2007.3333333333333	628
2007.6666666666667	628
2008	628
2008.3333333333333	628
2008.6666666666667	627
2009	627
2009.25	631
2009.5833333333333	629
2009.9166666666667	628
2010.25	630
2010.5833333333333	629
2010.9166666666667	629
2011.25	630
2011.5	629
2011.8333333333333	628
2012.1666666666667	629
2012.5	629
2012.8333333333333	628
2013.1666666666667	629
2013.5	629
2013.8333333333333	629
2014.0833333333333	629
2014.4166666666667	629
2014.75	629
2015.0833333333333	630
2015.4166666666667	629
2015.75	629
2016.0833333333333	628
2016.3333333333333	629
2016.6666666666667	628
2017	628
2017.3333333333333	629
2017.6666666666667	628
2018	628
2018.3333333333333	629
2018.5833333333333	629
2018.9166666666667	629
2019.25	630
2019.5833333333333	629
2019.9166666666667	629
2020.25	629
2020.5833333333333	628
2020.8333333333333	628
2021.1666666666667	628
2021.5	628
2021.8333333333333	627
2022.1666666666667	627
2022.5	629
2022.8333333333333	628
2023.1666666666667	628
2023.4166666666667	629
2023.75	629
2024.0833333333333	629
2024.4166666666667	629
2024.75	628
2025.0833333333333	628
2025.4166666666667	629
2025.6666666666667	628
2026	629
2026.3333333333333	629
2026.6666666666667	627

Rate and persistence

-1.09 Mm³

Mean drawdown per month over 12 months

10 of 24

Recent months below the 20th percentile for their own month

Rates are computed only across an unbroken run of months, so a rate is never divided by a period in which some of the change was not observed. Percentile counts compare each month with the same calendar month in every other year held.

Location

Lake Tschida

Gauge location

About this data

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	United States Bureau of Reclamation — Reservoir operations and Colorado River data · US Government work — public domain
How the values came to exist	Measured
Period held	1949–2026
Completeness	98.7% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	Storage is a managed quantity. A falling line can be a rule curve, a scheduled release or a transfer to another system rather than a shortage of water, and nothing here distinguishes them. No capacity figure on a stated basis is held for this reservoir, so no percentage of capacity is computed.
Continuity	99% of the months between 1949 and 2026 are held. Monthly means of the publisher's own daily record.
Last read from the publisher	2026-10-01
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

Use this data

Machine-readable JSON /api/v1/observations/by-subject/reservoir-usbr-402.json
How to cite this, and who you must credit
How these figures were produced
Request this at a different scale, format or geography

No bulk download is offered here, which is a licence position rather than a product one: at least one contributing publisher does not permit redistribution. The values can be read on the page, cited, and pointed to at source.

Attribution and citation

Suggested citation for Hydrionis

Hydrionis (2026), Lake Tschida reservoir records, accessed 2026-10-05, hydrionis.com/reservoirs/reservoir-usbr-402/

Cite Hydrionis where you rely on the compilation, the normalisation, the eligibility judgements or a chart. Where you use an unmodified published value, the publisher’s attribution is the one that is required; crediting Hydrionis as well is welcome and is not something Hydrionis can require of you.

Recommended, not required. Hydrionis does not claim rights over unmodified public data it relayed, and doing arithmetic on somebody else’s measurements does not make them Hydrionis’s. Cite the version and the access date: the Lake Tschida record changes as publishers release and as methods are revised, and a citation without both cannot be checked later. Full guidance is on cite and reuse.

None of the contributing licences requires attribution. Crediting the publishers is still good practice and they are listed above.

Where this comes from

924 monthly observations 1949–2026 Mm³

Spatially aggregatedHigh confidenceSeptember 2026

Source: USBR — Reservoir operations and Colorado River data, RISE catalogue item 549. Licence: Open.

Method: Monthly mean of the daily values published by the Bureau of Reclamation in acre-feet, converted to Mm³. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

Stored as a volume and not as a share of capacity: the operator publishes what is in the reservoir but not what it holds when full, so a percentage cannot be computed without inventing the denominator.

Retrieved 1 October 2026.

Monthly mean of the daily values published by the Bureau of Reclamation in acre-feet, converted to Mm³. Months with fewer than 20 days of record are not published rather than averaged from a partial month.